Device for reactivating cathode ray tubes



AP??? 1967 w. T. SADA DEVICE FOR REAGTIVATING CATHODE RAY TUBES Filed May 28, 1965 FIG. 2

II PROBE FIG.3

ATTORNEY United States Patent 3,313,588 DEVICE FOR REACTIVATING CATHODE RAY TUBES William T. Sada, 151 Nancy St, San Antonio, Tex. 78204 Filed May 28, 1965, Ser. No. 459,777 Claims. (Cl. 316-28) The present invention relates to a device for reactivating cathode ray tubes and more particularly to such a device for improving low cathode emission of a picture tube of a television receiver or the like.

An object of the present invention is the provision of a simple device which is interposed between a standard picture tube of a television receiver and the standard socket thereof to reactivate the cathode of the said picture tube.

Another object is to provide such a device which improves a picture tube having low cathode emission.

A further object of the invention is the provision of such a device using high frequency voltages present in the television receiver to improve the emission characteristics of the cathode of the picture tube.

Still another object is to provide such a device for improving the emission of the cathode of a picture tube in a television receiver wherein such reactivation occurs with the receiver in operative condition and wherein the repairman can visually observe the results of such process.

A final object of the present invention is to provide such a device which is inexpensive to manufacture, capable of mass production techniques, easy to use, and universal in its adaptability.

Other objects and features of the invention will become apparent to those skilled in the art as the disclosure is made in the following detailed description of preferred embodiments of the invention as ilustrated in the accompanyin g sheet of drawing in which:

FIG. 1 is a fragmentary, exploded view of the present invention in conjunction with a standard picture tube and a standard socket therefor.

FIG. 2 is an enlarged, side elevational view, partly broken away and partly in section, of the preferred embodiment of the invention.

FIG. 3 is a schematic representation of the circuitry within the device illustrated in FIG. 2.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a device for reactivating cathode ray tubes, in combination with the components with which the said device is associated. A conventional picture tube 11 used in a television receiver or the like includes a standard base 12; the said base has a centrally positioned, longitudinally and outwardly extending keyed pin 13 integrally formed with the said base, and a plurality of spaced prongs 14 concentric about the said pin and secured in the said base. Pin 13 and prongs 14 are normally received by the keyed receptacle 15 and female connectors 16 provided in a conventional socket 17, which socket connects by means of a cable 18 to the chassis. In the practice of the subject invention, the device 1!) is interposed between the picture tube 11 and the socket 17; one end of the said device accommodates the members on the base of the picture tube, while the members on the other end of the said device insert into the socket.

As best seen in FIG. 2 of the drawings, device 15 is essentially cylindrical and consists, in part, of a hollow, cylindrical casing 19 which terminates rearwardly in end 20 integrally formed therewith; the said casing is preferably constructed of plastic, ceramic or other insulating material. A disc 21, preferably of the same composition as the casing, is of the same outside diameter as the casing and includes a shoulder 22 of reduced diameter which inserts into the foremost end of said casing and is secured therein as by means of an adhesive or other suitable securing means. A centrally positioned keyed receptacle 23 and a plurality of spaced, female connectors 24 concentric therea bout are provided in the said disc in a conventional manner and accommodate pin 13 and prongs 14, respectively, of the picture tube 11.

In like manner, end 20 includes an integrally formed, longitudinally aligned and outwardly extending keyed pin 25; concentric thereabout are a plurality of spaced, outwardly extending prongs 25 secured in the base 20 as by conventional practices. The said pin 25 and prongs 26 are positioned in such a manner as to insert into the mating members in the socket 17.

As illustrated in FIGS. 1 and 2 of the drawings, a double pole, double throw switch 27 is secured to the side of the casing and the terminals thereof pass through .a bore (not shown) and communicate with the interior of the said casing. It is to be understood that the invention is not restricted to such type switch only but also includes a remote switch which connects to selected terminals within the casing by means of an elongated conductor which passes through a bore in the said casing. A test probe 28, such as is well known in the art, connects to selected terminals of the said switch by means of a conductor 29 which passes through bore 30 in the casing; an alligator clamp 31 or other clamping means connects to other selected terminals of the switch 27 by means of conductor 32 which passes through bore 33 in the said casing.

There is shown in FIG. 3 of the drawings the electrical circuit contained in the device 19. Female connectors 34-39 correspond to the female connectors 24 in disc 21, while male conectors 40-45 correspond to prongs 25 positioned in end 20 of the device. As will hereinafter he more fully described, switching means 27 is connected to only selected elements of the picture tube; the remaining elements of the said picture tube are not involved and means are provided merely to complete an electrical circuit through the device for such elements. More particularly, conductors 46-49 connect female connectors 34-37 to male connectors 4043, respectively.

It is to be understood that the subject invention may be used with picture tubes having either electrostatic or magnetic focusing means. For those picture tubes including electrostatic focusing means, as illustrated in the dotted line portions in FIG. 3, connectors 34, 40 are provided. Obviously such circuit is open if the picture tube does not contain electrostatic focusing means.

In such schematic diagram conductors 35, 41 and 36, 42 represent the filament connections, while conductors 37, 43 represent the connections to the screen grid of the picture tube. Female connectors 38 accommodates the cathode prong on the base of the picture tube, the said connector 38 is connected by conductor 50 to post 51 of switch 27; in like manner, female connector 39 accommodates the control grid prong on the base of the said picture tube and is connected by means of conductor 52 to post 53 of the said switch. Male connectors 44 connects to terminal 54 by means of conductor 55; the said conductor 44 inserts into the cathode connector in socket 17. Male connector 45 connects to terminal 56 by means of conductor 57, the said connector 45 inserts into the control grid connector in the said socket. Probe 28, heretofore mentioned, connects to terminal 58 of the switch by conductor 29, and clamp 31 connects to terminal 59 by means of conductor 32.

It is obvious that when switch 27 is thrown to a first position the ganged arms 6061 of the said switch contact terminals 54, 56 respectively whereby circuits are completed for male connectors 44, 45 to the corresponding female connectors 38, 39 and thence to the corresponding elements of the picture tube; in such position of the switch 27 the picture tube is operative in the same manner as when the said picture tube is inserted directly into socket 17. When the arms 6t 61 of the switch 27 are thrown to a second position, however, arm 63 contacts terminal 53 to which is connected probe 28; arm 61 simultaneously contacts terminal 59 to- Which clamp 31 is connected. In such second position of the switch, the cathode and control grid circuits as represented by connectors 44, 45 are open.

In operation, clamp 31 is connected to ground and power is applied to the television receiver; switch 27 is then thrown to the second position, heretofore mentioned. In such second position probe 28 is connected to the cathode of the picture tube and clamp 31 is connected to the control grid. Probe 28 is then tapped against the plate of the horizontal output tube of the television receiver whereby 4,000 to 5,000 volts at approximately 17,500 cycles per second and not exceeding 200 milliamps is applied to the cathode of the said picture tube while the filaments are energized with normal filament voltage. If the intensity of the light emitted by the picture tube does not increase appreciably, the probe is again tapped against the plate of the aforementioned tube. Alternatively, the probe may be tapped against the second anode of the picture tube which applies a fluctuating D.C. voltage to the said cathode. If the intensity of the light does not increase, a new picture tube is required. If the intensity of light increases, however, switch 27 may be turned to the first position whereby the repairman may visually observe the quality of the picture. The television receiver is turned off if such picture is acceptable, after which the device 10 is disconnected and the picture tube 11 inserted into socket 17.

It is believed that the improvement in the operating characteristics of the picture tube accrues from the application of high frequency voltages to the cathode whereby impurities, such as oxides, resulting from extensive use of the said picture tube, are dissipated or removed. In any event, of a large number of picture tubes having low cathode emission which were so treated, a large percentage were restored to serviceable condition and remained in such condition for extended periods of time.

It is to be understood, of course, that the foregoing disclosure relates to preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A device interposed between a picture tube and a socket therefor to improve low cathode emission of said picture tube comprising a casing having first and second ends, a plurality of female connectors in the first end of said casing, a plurality of male connectors on the second end of said casing, a switch having first and second throw positions mounted in said casing, a probe connected to said switch and a clamp connected to said switch where- :by in the first position of the said switch the picture tube is operative and in the second position of the said switch the probe connects to the cathode of said picture tube and the clamp connects to the control grid of the said picture tube.

2. A device interposed between a picture tube of a television receiver and a socket therefor to improve the cathode emission of the said picture tube comprising a casing having first and second ends, means in the first end to accommodate the picture tube, means on the second end to insert into the said socket, a switch in said casing, said switch having first and second throw positions, a test probe connected to said switch in said second throw position, a clamp connected to said switch in said second throw position, whereby in said second throw position said probe is connected to said cathode of the picture tube and said clamp is connected to the control grid of said picture tube.

3. The invention of claim 2 wherein said probe is connected to a high frequency source of alternating current.

4. The invention of claim 2 wherein a high frequency source is applied to the cathode of said picture tube.

5. The invention of claim 2 wherein a high frequency source from the plate of the horizontal output tube of the said television receiver is applied to the cathode of the picture tube.

No references cited.

RICHARD H. EANES, 111., Primary Examiner. 

1. A DEVICE INTERPOSED BETWEEN A PICTURE TUBE AND A SOCKET THEREFOR TO IMPROVE LOW CATHODE EMISSION OF SAID PICTURE TUBE COMPRISING A CASING HAVING FIRST AND SECOND ENDS, A PLURALITY OF FEMALE CONNECTORS IN THE FIRST END OF SAID CASING, A PLURALITY OF MALE CONNECTORS ON THE SECOND END OF SAID CASING, A SWITCH HAVING FIRST AND SECOND THROW POSITIONS MOUNTED IN SAID CASING, A PROBE CONNECTED TO SAID SWITCH AND A CLAMP CONNECTED TO SAID SWITCH WHEREBY IN THE FIRST POSITION OF THE SAID SWITCH THE PICTURE TUBE IS OPERATIVE AND IN THE SECOND POSITION OF THE SAID SWITCH THE PROBE CONNECTS TO THE CATHODE OF SAID PICTURE TUBE AND THE CLAMP CONNECTS TO THE CONTROL GRID OF THE SAID PICTURE TUBE. 